arcls: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/arcls - from package: nordugrid-arc-client

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/arcls - from package: nordugrid-arc-client

You may install the required package with command apt-get install {package}

Error in other languages:
arcls: bevel nie gevind nie
arcls: comandă negăsită
arcls: comando não encontrado
arcls: commande introuvable
arcls: command not found
arcls: käsku ei ole
arcls: không tìm thấy lệnh
arcls: komanda nerasta
arcls: Kommando nicht gefunden.
arcls: kommandot finns inte
arcls: komut yok
arcls: nie znaleziono polecenia
arcls: níor aimsíodh an t-ordú
arcls: no se encontró la orden
arcls: no s'ha trobat l'ordre
arcls: opdracht niet gevonden
arcls: parancs nem található
arcls: perintah tidak ditemukan
arcls: príkaz nenájdený
arcls: příkaz nenalezen
arcls: команда не найдена
arcls: командата не е открита
arcls: 命令找不到
arcls: コマンドが見つかりません